Q. No.The escape velocity from the Earth's surface is \(v\). The escape velocity from the surface of another planet having a radius, four times that of Earth and the same mass density is:
1.
\(3v\)
2.
\(4v\)
3.
\(v\)
4.
\(2v\)
A particle of mass \(m\) is projected with a velocity, \(v=kv_{e} ~(k<1)\) from the surface of the earth. The maximum height, above the surface, reached by the particle is:
(Where \(v_e=\) escape velocity, \(R=\) the radius of the earth)
| 1. | \(\dfrac{R^{2}k}{1+k}\) | 2. | \(\dfrac{Rk^{2}}{1-k^{2}}\) |
| 3. | \(R\left ( \dfrac{k}{1-k} \right )^{2}\) | 4. | \(R\left ( \dfrac{k}{1+k} \right )^{2}\) |
| 1. | \(\frac{S}{2},\frac{\sqrt{3gS}}{2}\) | 2. | \(\frac{S}{4}, \sqrt{\frac{3gS}{2}}\) |
| 3. | \(\frac{S}{4},\frac{3gS}{2}\) | 4. | \(\frac{S}{4},\frac{\sqrt{3gS}}{3}\) |
| 1. | \(\dfrac R {n^2}\) | 2. | \(\dfrac {R~(n-1)} n\) |
| 3. | \(\dfrac {Rn} { (n-1)}\) | 4. | \(\dfrac R n\) |
| 1. | \(180 ~\text{N/kg}\) | 2. | \(0.05 ~\text{N/kg}\) |
| 3. | \(50 ~\text{N/kg}\) | 4. | \(20 ~\text{N/kg}\) |
| List-I | List-II | ||
| (a) | Gravitational constant (\(G\)) | (i) | \([{L}^2 {~T}^{-2}] \) |
| (b) | Gravitational potential energy | (ii) | \([{M}^{-1} {~L}^3 {~T}^{-2}] \) |
| (c) | Gravitational potential | (iii) | \([{LT}^{-2}] \) |
| (d) | Gravitational intensity | (iv) | \([{ML}^2 {~T}^{-2}]\) |
| (a) | (b) | (c) | (d) | |
| 1. | (iv) | (ii) | (i) | (iii) |
| 2. | (ii) | (i) | (iv) | (iii) |
| 3. | (ii) | (iv) | (i) | (iii) |
| 4. | (ii) | (iv) | (iii) | (i) |
Assuming the earth to be a sphere of uniform density, its acceleration due to gravity acting on a body:
| 1. | increases with increasing altitude. |
| 2. | increases with increasing depth. |
| 3. | is independent of the mass of the earth. |
| 4. | is independent of the mass of the body. |
Two planets orbit a star in circular paths with radii \(R\) and \(4R,\) respectively. At a specific time, the two planets and the star are aligned in a straight line. If the orbital period of the planet closest to the star is \(T,\) what is the minimum time after which the star and the planets will again be aligned in a straight line?
| 1. | \((4)^2T\) | 2. | \((4)^{\frac13}T\) |
| 3. | \(2T\) | 4. | \(8T\) |
| 1. | \(+\dfrac K2\) | 2. | \(-\dfrac{K}{2}\) |
| 3. | \(-\dfrac{K}{4}\) | 4. | \(+\dfrac K4\) |
(\(G=\) gravitational constant)
| 1. | \(-\dfrac{20~Gm}{R}\) | 2. | \(-\dfrac{8~Gm}{R}\) |
| 3. | \(-\dfrac{12~Gm}{R}\) | 4. | \(-\dfrac{16~Gm}{R}\) |
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